Kidney stones and clogged arteries may be linked

NEW YORK (Reuters Health) - Young adults who've had kidney stones may also have an increased risk of clogged arteries, a new study says.

This does not mean that one causes the other, but instead the two conditions might have some common root cause, according to the paper published in the Journal of Urology.

"People who have kidney stones could be sort of the canary in the mine shaft," said Dr. Marshall Stoller, professor of urology at the University of California in San Francisco, and an author on the paper.

Slightly less than four percent of people had kidney stones at some point in the 20 year study. These people had about a 60-percent increased risk of getting clogged arteries later in their lives.

People tend to think of a kidney stone as a urinary problem, "but we need to be cognizant of the fact that the kidney is a blood filter," Stoller said, and can show signs of problems in the arteries as well.

High cholesterol, high blood pressure, smoking, and diabetes can all increase the risk of clogged arteries, which can lead to both heart attacks and strokes. These two diseases combined killed more than 589,000 people in 2005, according to the American Heart Association.

That people with kidney stones have an increased risk of clogged arteries is not really a surprise, said Andrew Evan, professor of medicine at Indiana University-Purdue University in Indianapolis, who was not involved in the study.

Previous studies have linked kidney stones with high blood pressure, which increases the risk of developing clogged arteries. But as far as what can lead to clogged arteries, "is it the higher blood pressure, or is it the kidney stones themselves?" Evan said. "We really don't know that."

About 5 percent of adults in the US have had kidney stones, according to the National Institute of Diabetes and Digestive and Kidney Diseases, a slightly higher proportion than in the study.

The study involved more than 5000 young adults between 18 and 30 years old who came back for exams at regular intervals over the next 20 years.

At the 20-year exam, the researchers analyzed the thickness of the wall of participants' carotid arteries. (A thicker-than-normal artery wall is a sign of the arteries getting clogged up.) And that's when they found that people who'd reported having kidney stones were 60 percent more likely to have clogged arteries, compared to people without kidney stones.

A problem with the study is that it included all people with kidney stones together in one group, Evans said. There are a number of different reasons people can get kidney stones such as too having much calcium in the urine, sustained dehydration, or a hereditary disorder. Not all may have an increased risk of clogged arteries, although more research is needed to shed some light on the issue.

In the meantime, you can reduce your risk of getting kidney stones by drinking enough to urinate about two liters a day and by cutting down on salt and meat, Stoller said.

And the American Heart Association advises that to reduce the risk of clogged arteries, people should exercise, eat a healthy diet, and not smoke.

"This is a warning sign," Stoller said. "The kidney stone is the tip of the iceberg."